U.S. patent number 7,454,106 [Application Number 11/837,862] was granted by the patent office on 2008-11-18 for factory spliced cable assembly.
This patent grant is currently assigned to ADC Telecommunications, Inc.. Invention is credited to John Clifton Cobb, III, Erik Gronvall, Yu Lu.
United States Patent |
7,454,106 |
Cobb, III , et al. |
November 18, 2008 |
Factory spliced cable assembly
Abstract
To optically couple a tether to a ribbonized distribution cable,
a cut is made in the distribution cable, exposing the ribbons
inside. The correct ribbon is located and spliced to a tether. A
splice protection sleeve is applied to the splice and placed into
the existing cut on the cable so as to be recessed within an outer
boundary of the cable jacket. The buffer tube from the tether cable
is also guided toward the cut and fixed in place. A breakout
assembly is installed on the distribution cable to secure the
tether to the distribution cable.
Inventors: |
Cobb, III; John Clifton
(Fitchburg, MA), Lu; Yu (Eden Prairie, MN), Gronvall;
Erik (Richfield, MN) |
Assignee: |
ADC Telecommunications, Inc.
(Eden Prairie, MN)
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Family
ID: |
38904859 |
Appl.
No.: |
11/837,862 |
Filed: |
August 13, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080080818 A1 |
Apr 3, 2008 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60950521 |
Jul 18, 2007 |
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60837481 |
Aug 14, 2006 |
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Current U.S.
Class: |
385/100 |
Current CPC
Class: |
G02B
6/4475 (20130101); G02B 6/4403 (20130101); G02B
6/4411 (20130101) |
Current International
Class: |
G02B
6/44 (20060101) |
Field of
Search: |
;385/100 |
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|
Primary Examiner: Pak; Sung H
Attorney, Agent or Firm: Merchant & Gould P.C.
Parent Case Text
CROSS REFERENCE INFORMATION
This application claims the benefit of U.S. Provisional Patent
Application Ser. No. 60/950,521, filed Jul. 18, 2007, and also
claims the benefit of U.S. Provisional Patent Application Ser. No.
60/837,481, filed Aug. 14, 2006, which applications are hereby
incorporated by reference in their entirety.
Claims
We claim:
1. A telecommunications cable comprising: a distribution cable
including a cable jacket and a ribbon stack positioned within the
cable jacket, the ribbon stack including a first ribbon, the first
ribbon including at least a first optical fiber of the first
ribbon, the distribution cable including a cut region where a
portion of the cable jacket has been removed and where at least the
first ribbon is accessible; and a tether that branches from the
distribution cable at the cut region, the tether including a tether
buffer tube surrounding at least a first optical fiber of the
tether, the first optical fiber of the tether being optically
coupled to the first optical fiber of the first ribbon at a
coupling location; wherein the coupling location is recessed within
an outer boundary defined by the cable jacket of the distribution
cable.
2. The telecommunications cable of claim 1, further comprising a
breakout assembly, the breakout assembly including at least a first
jacket support.
3. The telecommunications cable of claim 2, wherein the breakout
assembly includes a plurality of jacket supports arranged within
the cut region of the distribution cable.
4. The telecommunications cable of claim 2, wherein the first
jacket support includes a curved surface configured to extend over
the cut region, the first jacket support also including legs
configured to fit within the cut region.
5. The telecommunications cable of claim 2, wherein the first
jacket support has a length extending along a length of the cut
region.
6. The telecommunications cable of claim 1, further comprising a
transition block mounted to the distribution cable, the transition
block being configured to secure the tether to the distribution
cable.
7. The telecommunications cable of claim 6, wherein the transition
block provides a path along which the first optical fiber of the
tether extends into the distribution cable at the cut region.
8. The telecommunications cable of claim 1, further comprising a
second tether that branches from the distribution cable at the cut
region, the second tether including a second tether buffer tube
surrounding an optical fiber of the second tether.
9. The telecommunications cable of claim 1, further comprising a
splice sleeve mounted over the coupling location within the outer
boundary.
10. A telecommunications cable comprising: a distribution cable
including a cable jacket and a ribbon stack positioned within the
cable jacket, the ribbon stack including a first ribbon, the first
ribbon including at least a first optical fiber of the first
ribbon, the distribution cable including a cut region where a
portion of the cable jacket has been removed and where at least the
first ribbon is accessible; a tether that branches from the
distribution cable at the cut region, the tether including a tether
buffer tube surrounding at least a first optical tether fiber, the
first optical tether fiber being optically coupled to the first
optical fiber of the first ribbon at a coupling location recessed
within an outer boundary defined by the cable jacket of the
distribution cable; and a block defining a cable channel and a
tether channel arrangement, the cable channel being configured to
receive the distribution cable to mount the block to the
distribution cable, the tether channel arrangement configured to
receive the first tether fiber from the tether and to transition
the first tether fiber into the distribution cable at the cut
region, the block being securely coupled to the tether to anchor
the tether to the distribution cable.
11. The telecommunications cable of claim 10, wherein the block
extends from a first end to a second end and the cable channel
extends from the first end of the block to the second end.
12. The telecommunications cable of claim 10, wherein the tether
channel arrangement includes a first tether channel and a second
tether channel, the first tether channel being adapted to receive
at least the first tether fiber and the second tether channel being
adapted to receive at least a second tether fiber.
13. The telecommunications cable of claim 12, wherein the second
tether fiber is included within a second tether coupled to the
distribution cable.
14. The telecommunications cable of claim 10, further comprising a
jacket support mounted in the distribution cable at the cut
region.
15. The telecommunications cable of claim 14, wherein the jacket
support extends along a length of the cut region.
16. The telecommunications cable of claim 14, wherein the jacket
support includes a flange curved to match an outer diameter of the
cable jacket of the distribution cable.
17. The telecommunications cable of claim 16, wherein the jacket
support includes at least a first leg that projects outwardly from
the flange, the first leg being sized to fit within the cut region
of the distribution cable.
18. The telecommunications cable of claim 17, wherein the first leg
is sufficiently long to extend through the cable jacket.
19. The telecommunications cable of claim 10, further comprising an
over-mold that encloses and seals the distribution cable at the cut
region.
20. The telecommunications cable of claim 10, wherein a
cross-sectional area taken at any point along the
telecommunications cable is less than one inch in diameter.
Description
TECHNICAL FIELD
The principles disclosed herein relate to fiber optic cable
systems. More particularly, the present disclosure relates to fiber
optic cable systems having main cables and branch cables.
BACKGROUND
Passive optical networks are becoming prevalent in part because
service providers want to deliver high bandwidth communication
capabilities to customers. Passive optical networks are a desirable
choice for delivering high speed communication data because they
may not employ active electronic devices, such as amplifiers and
repeaters, between a central office and a subscriber termination.
The absence of active electronic devices may decrease network
complexity and/or cost and may increase network reliability.
FIG. 1 illustrates a network 100 deploying passive fiber optic
lines. As shown in FIG. 1, the network 100 may include a central
office 110 that connects a number of end subscribers 115 (also
called end users 115 herein) in a network. The central office 110
may additionally connect to a larger network such as the Internet
(not shown) and a public switched telephone network (PSTN). The
network 100 may also include fiber distribution hubs (FDHs) 130
having one or more optical splitters (e.g., 1-to-8 splitters,
1-to-16 splitters, or 1-to-32 splitters) that generate a number of
individual fibers that may lead to the premises of an end user 115.
The various lines of the network can be aerial or housed within
underground conduits (e.g., see conduit 105).
The portion of network 100 that is closest to central office 110 is
generally referred to as the F1 region, where F1 is the "feeder
fiber" from the central office. The F1 portion of the network may
include a distribution cable having on the order of 12 to 48
fibers; however, alternative implementations may include fewer or
more fibers. The portion of network 100 that includes an FDH 130
and a number of end users 115 may be referred to as an F2 portion
of network 100. Splitters used in an FDH 130 may accept a feeder
cable having a number of fibers and may split those incoming fibers
into, for example, 216 to 432 individual distribution fibers that
may be associated with a like number of end user locations.
Referring to FIG. 1, the network 100 includes a plurality of
break-out locations 125 at which branch cables are separated out
from main cable lines. Breakout locations can also be referred to
as tap locations, drop cable locations, splice locations or branch
locations. Branch cables can also be referred to as drop cables,
drop lines, breakout cables or stub cables. Branch cables are often
connected to drop terminals 104 that include connector interfaces
for facilitating coupling the fibers of the branch cables to a
plurality of different subscriber locations.
Branch cables can manually be separated out from a main cable in
the field using field splices. Field splices are typically housed
within sealed splice enclosures. Manual splicing in the field is
time consuming and expensive.
As an alternative to manual splicing in the field, pre-terminated
cable systems have been developed. Pre-terminated cable systems
include factory integrated breakout locations manufactured at
predetermined positions along the length of a main cable (e.g., see
U.S. Pat. Nos. 4,961,623; 5,125,060; and 5,210,812). However,
existing pre-terminated cable systems can be expensive because
extra connectors at intermediate connection locations are often
used. Moreover, the installation of pre-terminated cables can be
difficult. For example, for underground applications,
pre-terminations can complicate passing pre-terminated cable
through the underground conduit typically used to hold fiber optic
cable (e.g., 1.25 inch inner diameter conduit). Similarly, for
aerial applications, pre-terminations can complicate passing
pre-terminated cable through aerial cable retention loops.
SUMMARY
Certain aspects of the disclosure relate to fiber optic cable
systems, packaging configurations and methods that facilitate the
effective use and installation of pre-terminated fiber optic
cable.
A variety of additional inventive aspects will be set forth in the
description that follows. The inventive aspects can relate to
individual features and to combinations of features. It is to be
understood that both the forgoing general description and the
following detailed description are exemplary and explanatory only
and are not restrictive of the broad inventive concepts upon which
the embodiments disclosed herein are based.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a prior art passive fiber optic network;
FIG. 2 is a cross-sectional view of an example distribution cable
according to one embodiment of the present disclosure;
FIG. 3 is a cross-sectional view of an example tether according to
one embodiment of the present disclosure;
FIG. 4 is a schematic view of an example tether coupled to a
distribution cable at a breakout location according to one
embodiment of the present disclosure;
FIG. 5 is a top view of a distribution cable having a cut region
according to one embodiment of the present disclosure;
FIG. 6A is a top view of a tether prepared to be optically coupled
to the distribution cable of FIG. 5;
FIG. 6B is a top view of the tether of FIG. 6A including a
multi-fiber connector located at the end of the tether;
FIG. 7 is a perspective view of a first breakout assembly installed
on a distribution cable at a breakout location according to one
embodiment of the present disclosure;
FIG. 8 is a front perspective view of an example jacket support
according to one embodiment of the present disclosure;
FIG. 9 is an end view of the jacket support of FIG. 8;
FIG. 10 is a side view of the jacket support of FIG. 8;
FIG. 11 is a bottom view of the jacket support of FIG. 8;
FIG. 12 is a perspective view of the distribution cable of FIG. 7
with an over-mold installed over the breakout location according to
one embodiment of the present disclosure;
FIG. 13 is a perspective view of a second breakout assembly
installed on a distribution cable at a breakout location according
to one embodiment of the present disclosure;
FIG. 14 is a side view of an example transition block according to
one embodiment of the present disclosure;
FIG. 15 is a perspective view of the transition block of FIG.
14;
FIG. 16 is an end view of the transition block of FIG. 14;
FIG. 17 is a partial, schematic view of the breakout assembly of
FIG. 13 in which the tether is mounted to a first body member of
the transition block and routed into the cut region of the
distribution cable and in which the second body member of the
transition block has been removed;
FIG. 18 is a perspective view of the distribution cable of FIG. 13
with an over-mold installed over the breakout location according to
one embodiment of the present disclosure;
FIGS. 19-23 show another jacket support having features that are
examples of inventive aspects in accordance with the principles of
the present disclosure;
FIGS. 24-28 show a further jacket support having features that are
examples of inventive aspects in accordance with the principles of
the present disclosure;
FIGS. 29-33 show still another jacket support having features that
are examples of inventive aspects in accordance with the principles
of the present disclosure;
FIGS. 34 and 35 are cross-sectional views showing the jacket
support of FIGS. 29-33 mounted in a cut region of a distribution
cable;
FIG. 36 shows another breakout assembly having features that are
examples of inventive aspects in accordance with the principles of
the present disclosure;
FIGS. 37-43 are various views of an anchor block of the breakout
assembly of FIG. 36;
FIGS. 44-51 are various views of a first piece of the anchor block
of FIGS. 37-43;
FIGS. 52-59 are various views of a second piece of the anchor block
of FIGS. 37-43;
FIGS. 60-63 are various views of a cable reinforcing member having
features that are examples of inventive aspects in accordance with
the principles of the present disclosure;
FIG. 64 is a cross-sectional view showing a pair of the reinforcing
members of FIGS. 60-63 being used to reinforce a distribution
cable;
FIGS. 65-67 are various views of another cable reinforcing member
having features that are examples of inventive aspects in
accordance with the principles of the present disclosure; and
FIG. 68 is a cross-sectional view showing a pair of the reinforcing
members of FIGS. 65-67 being used to reinforce a distribution
cable.
DETAILED DESCRIPTION
The present disclosure relates to mid-span breakout arrangements
provided on distribution cables. Each breakout arrangement is
provided at a breakout location to protect the optical coupling of
a tether to a distribution cable. A typical distribution cable
includes a relatively large number of fibers (e.g., 72, 144 or more
fibers). The fibers are typically organized within ribbons in a
central portion of the distribution cable.
For example, FIG. 2 shows an example distribution cable 220
including a central buffer tube 222 enclosing a ribbon stack 225.
Typically, a ribbon stack 225 includes approximately twelve ribbons
and each ribbon contains about twelve fibers 224.sub.dc. For
clarity, only twelve fibers 224.sub.dc in the ribbon stack 225 are
shown. The buffer tube 222 may include dry, water-blocking
materials 228, such as yarn and/or tape. The distribution cable 220
also includes at least one, and preferably two or more, strength
members 226 (e.g., flexible rods formed by glass fiber reinforced
epoxy) for reinforcing the cable 220. An outer strength member (not
shown), such as aramid fiber/yarn (e.g., Kevlar.RTM.), can surround
the single buffer tube 222 within the jacket 230. The distribution
cable 220 further includes an outer jacket 230 that encloses the
ribbon stack 225 and the strength members 226. Ripcords 232 can be
provided for facilitating tearing away portions of the jacket 230
to access the fibers of the ribbon stack 225 within the jacket
230.
A typical mid-span breakout location is provided at an intermediate
point along the length of a distribution cable (e.g., see FIG. 4).
Commonly a tether (e.g., a drop cable or a stub cable) branches out
from the distribution cable at the breakout location. The tether
most commonly has a fewer number of fibers as compared to the
number of fibers provided within the distribution cable. In an
example embodiment, the tether has no more than twelve fibers. The
tether includes fibers that extend between first and second ends.
The first ends of the tether fibers are preferably spliced to
selected fibers of the distribution cable at the breakout location.
The second ends of the tether fibers can either be connectorized or
unconnectorized. In one embodiment, the end of each tether is
connectorized with a multi-fiber connector having a multi-fiber
ferrule in which the second ends of the tether fibers of the
corresponding tether are mounted.
FIG. 3 illustrates a tether cable 240 configured to join to the
distribution cable 220 (e.g., at a breakout location 260). The
tether 240 is depicted as having a flat cable configuration. The
flat cable configuration includes a central buffer tube 242
containing a plurality of fibers 224.sub.t (e.g., typically one to
twelve loose or ribbonized fibers). Strength members 246 (e.g.,
flexible rods formed by glass fiber reinforced epoxy) are
positioned on opposite sides of the central buffer tube 242. An
outer jacket 250 surrounds the strength members 246 and the buffer
tube 242.
In the example shown, the outer jacket 250 includes an outer
perimeter having an elongated transverse cross-sectional shape. An
additional strength layer 248 (e.g., aramid fiber/yarn) can be
positioned between the buffer tube 242 and the outer jacket 250. As
shown at FIG. 3, the transverse cross-sectional shape includes
oppositely positioned, generally parallel sides 252 interconnected
by rounded ends 254. However, any suitable cable configuration can
be utilized for both the distribution cable and the tether
cable.
Referring now to FIG. 4, one or more tethers 240 can optically
couple to a distribution cable 220. Each tether 240 branches
outwardly from the distribution cable 220 at a breakout location
260. The breakout location 260 includes a coupling location 280
where selected ribbonized fibers 224.sub.dc of the distribution
cable 220 are optically coupled (e.g., spliced) to corresponding
fibers 224.sub.t of the tether 242. It is preferred for the fibers
224.sub.t of the tether to be pre-terminated to the fibers
224.sub.dc of the distribution cable. "Pre-terminated" means that
the fibers 224.sub.t are fused (e.g., spliced) or otherwise
optically coupled to the fibers 224.sub.dc of the distribution
cable 220 at the factory as part of the cable manufacturing process
rather than being field terminated. The remainder of the breakout
assembly 200 is also preferably factory installed.
In general, the coupling location 280 is recessed within the outer
jacket 230 of the distribution cable 220 along with the ribbonized
fibers 224.sub.dc and an end portion of the tether buffer tube 242.
Positioning the coupling location 280 within the outer jacket 230
of the distribution cable 220 provides a smaller transverse
cross-section of the breakout location 260.
Referring now to FIG. 5, to prepare the breakout location 260 on
the distribution cable 220, a portion of the jacket 230 and the
buffer tube 222 is first cut away to provide a cut region 270
(e.g., a rectangular access slot cut through the jacket 230 and the
buffer tube 222). The cut region 270 extends along a length L from
a first end 272 and a second, opposite end 274. The ribbon stack
225 is accessible through the cut region 270. One or more of the
ribbons of the ribbon stack 225 are then selected and the fibers
224.sub.dc of the selected ribbons are accessed. With the
distribution cable 220 prepared as shown in FIG. 5, the fibers
224.sub.dc are ready to be terminated to a prepared tether 240.
To prepare the tether 240 to be incorporated into the breakout
assembly 300 (e.g., see FIG. 7), a portion of the outer jacket 250
is stripped away to expose the central buffer tube 242 and the
strength members 246 (see FIG. 6A). As shown at FIG. 6A, the
central buffer tube 242 and the strength members 246 project
outwardly beyond an end 258 of the outer jacket 250. The strength
layer 248 has been removed from around the buffer tube 242. After
removing the outer jacket 250, an end portion of the central buffer
tube 242 is removed to expose the fibers 224.sub.t. FIG. 6B shows
the tether 240 including a multi-fiber connector 251 (e.g., a 12
fiber multi-fiber connector having a ferrule 253 that can receive
12 fibers) located at the end of the tether distal from the
breakout location 260. Once again, the end of the tether 240
prepared to be mechanically and optically coupled to the
distribution cable 220 at the breakout location 260 includes end
portions of fibers 224t exposed from the buffer tube 242. Also, the
jacket 250 has been stripped to expose end portions of the buffer
tube 242 and the strength members 246. A mechanical crimp member
255 can be crimped to exposed end portions of the strength members
246. In other embodiments, the crimp member can be crimped over the
tether jacket 250.
The prepared tether 240 is optically coupled to the distribution
cable 220 at the coupling location 280 using known coupling
techniques (e.g., a fusion splice technique). A coupling protector
(i.e., a splice protection sleeve) can be positioned over the
spliced fibers 224.sub.dc, 224.sub.t at the coupling location 280.
Typically, the coupling protector is configured to heat shrink to
fit the fibers 224. For example, the coupling protector can include
a strength member, inner meltable adhesive tube, and polyolefin
outer tube. The strength member of the coupling protector can be
stainless steel or fiberglass. Example splice protection sleeves
are disclosed at U.S. Pat. No. 5,731,051, that is hereby
incorporated by reference in its entirety. It will be appreciated
that a splice sleeve can hold/protect a single splice or multiple
splices. In one embodiment, one splice sleeve is used to hold all
of the splices corresponding to a given tether.
The coupling protector is inserted within the cut region 270 of the
distribution cable 220 so as to be recessed below/inside the cable
jacket 230 as shown in FIG. 4. In one embodiment, the outer
perimeter (i.e., the outer diameter) of the cable jacket 230
defines an outer boundary within which the coupled fibers
224.sub.dc, 224.sub.t are arranged. In a preferred embodiment, an
end portion of the tether buffer tube 242 can also be inserted
within the outer boundary through the cut region 270. The buffer
tube 242 and coupling protector can be secured using tape,
adhesive, or any desired fastener. The tether 240 can be secured to
the distribution cable 220 adjacent the cut region 270 using a
breakout assembly as described herein.
Referring now to FIGS. 7-12, one example of a breakout assembly 300
having features that are examples of inventive aspects in
accordance with the principles of the present disclosure is shown.
In the example shown in FIG. 7, the breakout assembly 300 includes
jacket supports 320, a fastener 330, and a spacer 340. The fastener
330 secures the tether 240 to the distribution cable 220 at the
second end 274 of the cut region 270. In one embodiment, the
fastener 330 includes a strip of tape wound around the tether 240
and the distribution cable 220. In another embodiment, the fastener
330 includes a hose clamp.
The spacer 340 is located at the first end 272 of the cut region
270. The spacer is generally configured to protrude radially
outwardly from the distribution cable a distance of less than about
0.2 inches. In one example embodiment, the spacer 340 includes a
strip of tape wound multiple times around the distribution cable
220 adjacent the first end 272 of the cut region 270. In other
embodiments, however, the spacer 340 can include any desired
structure configured to protrude radially outwardly from the
distribution cable 220.
The jacket supports 320 are positioned within the cut region 270 to
inhibit excess bending of the ribbon stack 225 along the cut region
270. In the example shown in FIGS. 8-11, the jacket supports 320
include legs 324 configured to fit within the cut region 270 of the
distribution cable 220 and a curved surface 322 configured to
extend over the cut region 270. In general, the jacket supports 320
have a length L' ranging from about 0.5 inches to about 2 inches, a
width W' ranging from about 0.25 inches to about 0.75 inches, and a
depth D' of about 0.1 inches to about 0.4 inches. Typically, the
jacket supports 320 have a length L' of about 1.0 inches, a width
W' of about 0.37 inches, and a depth D' of about 0.2 inches.
FIGS. 20-23 and 24-28 respectively show two alternative jacket
supports 520a, 520b adapted for use in reinforcing the cut region
270 of a breakout location. The jacket supports 520a, 520b have
flanges 521a, 521b that are curved to match the outer diameter of
the cable jacket 230. The jacket supports 520a, 520b also include
legs 524a, 524b that project outwardly from the flanges 521a, 521b.
The legs 524a, 524b are sized to fit within the cut region 270.
When installed at the cut region 270, the legs 524a, 524b fit
within the cut region 270 and the flanges overlap the outer
diameter of the cable jacket 230 at opposite sides of the cut
region 270. The leg 524a has a length L1 that is longer than a
corresponding length L2 of the leg 524b. The length L1 is selected
so that the leg 524a is sufficiently long to extend through the
cable jacket 230 and at least partially into the buffer tube 222
when the jacket support 520a is mounted at the cut region 270. The
length L2 is selected so that the leg 524b does not extend into the
buffer tube 222 when the jacket support 520b is mounted at the cut
region 270. To reinforce the full cut region 270, it is preferred
for a plurality of the jacket supports 520a and a plurality of the
jacket supports 520b to be positioned along the length of the cut
region 270. To provide clearance within the cable 220 for the
splice sleeves, the jacket supports 520b can be mounted at
locations of the cut region 270 in which the jacket supports are
arranged to cover the splice sleeves. In contrast, the jacket
supports 520a can be mounted at locations of the cut region 270
that are axially offset from the splice sleeves. Typically, the
jacket supports 520b will be arranged at a mid-region of the cut
region 270, and the jacket supports 520a will be arranged adjacent
the ends 272, 274 of the cut region 270.
FIGS. 29-33 show another jacket support 620 adapted for use in
reinforcing the cut region 270 of a breakout location. The jacket
support 620 is a reinforcing strip having a length that generally
equals the length of the cut region 270. The jacket support 620 has
a flange 621 that are curved to match the outer diameter of the
cable jacket 230. The jacket support 620 also includes legs 624a,
624b that project outwardly from the flange 621. The legs 624a,
624b are sized to fit within the cut region 270. When installed at
the cut region 270, the legs 624a, 624b fit within the cut region
270 and the flange 621 overlaps the outer diameter of the cable
jacket 230 at opposite sides of the cut region 270. The leg 624a
has a length L1 that is longer than a corresponding length L2 of
the leg 624b. The length L1 is selected so that the leg 624a is
sufficiently long to extend through the cable jacket 230 and at
least partially into the buffer tube 222 (see FIG. 34) when the
jacket support 620 is mounted at the cut region 270. The length L2
is selected so that the leg 624b does not extend into the buffer
tube 222 (see FIG. 35) when the jacket support 620 is mounted at
the cut region 270. Flex locations 626 are provided between the
legs of the jacket support 620 to allow the jacket support 620 to
flex with the distribution cable 220. When assembled at the cut
region 270, splice sleeves are preferably mounted beneath the legs
640b to provide clearance for the splice sleeves.
The breakout assembly 300 also includes an over-mold 350 that
encloses and seals the cut region 270 of the distribution cable 220
from the fastener 330 to the ends of the tether strength members
246 (e.g., see FIG. 12). In certain embodiments, a wrap of heat
resistant tape (e.g., silicone tape) can provide an intermediate
layer between the distribution cable 220 and the over-mold 350.
The over-mold 350 is preferably made of a flexible polymer plastic
material. It is preferred for the over-mold 350 to be sized with a
cross sectional shape sufficient to allow the breakout location to
be readily passed through a one and one-half inch inner diameter
conduit or a one and one-quarter inch diameter conduit. In certain
embodiments, the breakout location 260 has a cross sectional area
that can be passed through a one inch inner diameter conduit.
Referring now to FIGS. 13-18, an alternative example of a breakout
assembly 400 having features that are examples of inventive aspects
in accordance with the principles of the present disclosure is
shown. The breakout assembly 400 includes a coupling protector
(e.g., as described above) positioned over the fibers 224.sub.dc,
224.sub.t at the coupling location 280.
In the example shown in FIG. 13, the breakout assembly 400 includes
at least one jacket support 420 and a transition block 430. In
general, the jacket supports 420 resemble the jacket supports 320
discussed above with reference to FIGS. 7-12. In a preferred
embodiment, three jacket supports 420 are provided in the cut
region 270 of the distribution cable 220. For clarity, two jacket
supports 420 are shown in FIG. 13.
The transition block 430 secures the tether 240 to the distribution
cable 220 at the second end 274 of the cut region 270. The strength
members 246 of the tether 240 can be secured to the transition
block 430 to strengthen the mechanical interface between the tether
240 and the distribution cable 220. The transition block 430 can
also provide a path along which the tether buffer tube 242 can be
routed into the cut region 270 of the distribution cable 220.
In certain embodiments, the transition block 430 includes two body
members configured to secure together. In some embodiments, the two
body members are mirror-images of one another. In other
embodiments, however, one of the body members is wider than the
other body member to facilitate mounting the tether 240 to the
wider body member. For example, FIGS. 14-16 illustrate a first body
member 430A configured to couple to a narrower body member (not
shown) to form the transition block 430 shown in FIG. 13.
The body member 430A extends along a length L'' from a first end
431 to a second, opposite end 433. The body member 430A has a top
side 437 and a bottom side 439. The bottom side 439 of the body
member 430A defines a first channel 432 configured to receive the
outer jacket 230 of the distribution cable 220. The first channel
432 extends substantially linearly from the first end 431 to the
second end 433 of the body member 430A.
In general, the body member 430A has a length L'' ranging from
about 1.5 to about 3.0 inches, a width W'' ranging from about 0.25
inches to about 1.0 inches, and a depth D'' ranging from about 0.75
to about 1.25 inches. In a preferred embodiment, the body member
430A has a length L'' of about 2 inches, a width W'' of about 0.4
inches and a depth D'' of about 1 inch. The transition block 430
has a width equal to the width W'' of the first body member 430A
and the width of the second body member (not shown). In one example
embodiment, the transition block 430 has a width of about 0.7
inches.
The top side 437 of the body member 430A defines a second channel
434 configured adjacent the first end 431 to extend generally
parallel with the first channel 432 and configured adjacent the
second end 433 to taper downwardly to the first channel 432. A
separating member 435 extends between and defines the first and
second channels 432, 434. The separating member 435 can include a
fastening member 436 configured to engage with a corresponding
fastening member on the second body member (not shown). In a
preferred embodiment, the fastening member 436 can include a hole
configured to receive a protruding fastening member on the second
body member.
As shown in FIG. 17, the second channel 434 is configured to
receive the tether 240 at the first end 431 and to route the tether
240 into the cut region 270 of the distribution cable 220. In a
preferred embodiment, the second channel 434 is configured to
receive the outer jacket 250 of the tether 240 at the first end 431
(see FIG. 17). In some embodiments, the strength members 246 of the
tether 240 can be secured to the body member 430A adjacent the
tapered portion of the second channel 434 (see FIG. 17). For
example, the second channel 434 can include a pair of strength
member receptacles 435 for receiving the strength members 246. The
strength members 246 can be adhesively bonded within the
receptacles 435. Further, a pocket 447 can be provided for
receiving the mechanical crimp member 255 crimped to the tether to
provide a further mechanical coupling between the tether 240 and
the transition block 430. In other embodiments, however, the body
member 430A can be configured to receive and hold the strength
members 246 at any point along the second channel 434.
The transition block 430 also includes further structure for
providing an effective mechanical interface with the tether 240.
For example, the second channel 434 includes an end opening 459
sized to match the outer shape of the outer jacket 250 of the
tether 240. Also, a buffer tube receptacle 449 for receiving the
exposed buffer tube 242 of the prepared tether 240 is defined
between the receptacles 435 that receive the exposed strength
members 246 of the prepared tether 240.
The breakout assembly 400 can also includes an over-mold 450 that
encloses and seals the cut region 270 of the distribution cable 220
from the transition block 430 to adjacent the first end 272 of the
cut region 270 (e.g., see FIG. 18). In certain embodiments, a wrap
of heat resistant tape (e.g., silicone tape) can provide an
intermediate layer between the distribution cable 220 and the
over-mold 450.
The over-mold 450 is preferably made of a flexible polymer plastic
material. It is preferred for the over-mold 450 to be sized with a
cross sectional shape sufficient to allow the breakout location to
be readily passed through a one and one-half inch inner diameter
conduit or a one and one-quarter inch diameter conduit. In certain
embodiments, the breakout location 260 has a cross sectional area
that can be passed through a one inch inner diameter conduit.
Referring now to FIG. 36, an alternative example of a breakout
assembly 700 having features that are examples of inventive aspects
in accordance with the principles of the present disclosure is
shown. The breakout assembly 700 includes two splice protectors 701
(e.g., as described above) positioned over splices between the
fibers 224.sub.dc, 224.sub.t. It will be appreciated that the
fibers 224.sub.dc, 224.sub.t depicted at FIG. 36 are each
representative of a plurality of fibers (e.g., 12 fibers in the
case of 12 fiber tethers). The breakout assembly 700 also includes
the jacket support 620 of FIGS. 29-33, which is mounted in the cut
region 270 of the breakout location. The splice protectors 701 are
located within the jacket 230 of the distribution cable 220 at
locations beneath the shorter legs 624b of the jacket support 620.
The breakout assembly further includes a block 704 that functions
to transition the fibers 224t from the distribution cable 220 to
the tethers 240, and also functions to anchor the tethers 240 to
the distribution cable 220. The jacket support 620 includes a tab
661 that overlaps the block 704 to resist relative movement between
the block 704 and the jacket support 620.
Referring to FIGS. 39-43, the block 704 includes a cable channel
705 for receiving the distribution cable 220. The cable channel 705
is generally straight and extends from a first open end 707 to a
second open end 709. The cable channel 705 receives the
distribution cable 220 and allows the distribution cable 220 to
pass through the block 704. It will be appreciated that the jacket
230 of the distribution cable 220 cab be adhesively bonded within
the channel 705 such that the block 704 is mechanically anchored to
the cable 220.
The block 704 also includes a tether channel arrangement 710
adapted for anchoring two tethers 240 to the block 704. The tether
channel arrangement includes first and second tether channels 712
each adapted for receiving a tether 240. Similar to previous
embodiments, the channels 712 can include structures for
mechanically coupling the tethers to the block 704. For example,
the tether channels 712 can include crimp pockets for receiving
mechanical crimps coupled to the tethers, strength member
receptacles for facilitating bonding the tether strength members to
the block 704, and other structures.
The block 704 has a two piece configuration including pieces 704a,
704b that interconnect by a hinged, snap fit configuration. A hinge
720 is defined between the pieces 704a, 704b by tabs 722 of piece
704b that fit within openings 724 of piece 704a. A snap fit
connection is provided between the pieces 704a, 704b by flexible
cantilever latches 726 of piece 704b that fit within receivers 728
of piece 704a. To mount the block 704 on the distribution cable
220, the tabs 722 are inserted within the openings 724 and the
cable 220 is inserted between the pieces 704a, 704b in alignment
with the cable channel 705. The two pieces 704a, 704b are then
pivoted toward one another about hinge line 730 thereby capturing
the cable 220 within the cable channel 705. The pieces 704a, 704b
are pivoted toward one another until the cantilever latches 726
snap within the receivers 728 thereby securing the pieces 704a,
704b together.
The block 704 includes other features for enhancing the breakout
location. For example, piece 704a includes a lug 733 that fits
within the cut region 270 to maintain rotational alignment between
the distribution cable 220 and the block 704 during assembly (i.e.,
the lug prevents fits within the cut region 270 to prevent relative
rotation from occurring between the block 704 and the distribution
cable 220). Also, piece 704a includes an overlap member 735 that
fits within a receptacle 737 of piece 704b to minimize any fiber
pinch locations that may be present between the pieces 704a, 704b.
Further, piece 704a includes an integral hook 739 for receiving the
buffer tube 242 of one of the tethers 240 to retain the buffer tube
242 in close proximity to the piece 704a.
The cable channel 705 of the block 704 also includes a tapered
diameter 740 adjacent the second open end 709. The tapered diameter
740 enlarges as the channel 705 extends toward the second open end
709. Prior to assembling the block 704 on the distribution cable
220, tape is wrapped about the cable at a location slightly offset
from the end 274 of the cut region 270. By mounting the block 704
on the cable 220, and then sliding the block 704 axially along the
cable toward the tape, the tape is received and compressed within
the tapered diameter 740 to assist in sealing the second open end
709 of the cable channel 705.
In each of the above-described breakout arrangements, a cut region
or slot was provided in the cable jacket 230 and buffer tube 222.
Because the cable 220 has been compromised, flexing of the cable
can cause distortion of the cable cross-section and/or movement of
the strength member 226 within the cable 220. To protect the splice
location, further reinforcement can be provided to resist cable
distortion and/or strength member movement. FIGS. 60-63 show an
example reinforcing member 800 that can be used to further
reinforce the cable 220 at the cut region 270. The reinforcing
member 800 is a bendable metal clip having a hook end 802 and a
fastening end 804. The fastening end 804 includes a strap 806 and a
strap receiver 808. In practice, a pair of the reinforcing members
800 are used together to reinforce the cable 220. As shown at FIG.
64, the hook ends 802 are inserted through the cut region 270 and
hooked over the cut edges of the jacket 230 and the buffer tube
222. The bodies of the reinforcing members 800 are bent around the
outer diameter of the jacket 230 and fastening ends 804 are
fastened together at the side of the cable 220 opposite form the
cut region 270. The members 800 are fastened together by inserting
the straps 806 through the receivers 808, and bending the straps
806 while pulling the straps tight.
FIGS. 65-68 show another reinforcing member 900 that can be used to
further reinforce the cable 220 at the cut region 270. The
reinforcing member 900 is a buffer tube spreader that fits within
the buffer tube 222 as shown at FIG. 68 to assist in holding the
buffer tube open. The reinforcing member 900 includes an insert
portion 902 that fits within the cut region 270, and spreader wings
904 that angle outwardly from the insert portion 902. For certain
applications, the reinforcing members 800 and 900 can be used
separately or in combination with one another to reinforce a
distribution cable.
The above specification provides examples of how certain inventive
aspects may be put into practice. It will be appreciated that the
inventive aspects can be practiced in other ways than those
specifically shown and described herein without departing from the
spirit and scope of the inventive aspects.
* * * * *
References